One idea could be a rengoku fanfic where he trains a new group of young slayers. It could focus on his unique teaching methods and how he instills his values in them.
Tanjiro would be a great character to pair with rengoku. Their different personalities could create an interesting interaction. Tanjiro's kind - hearted nature and rengoku's fiery determination could lead to some great storylines.
Stir-frying was one of the common methods of cooking Chinese dishes. It was a cooking process in which one or several dishes were placed in a special concave pot, and the heat transmitted from the fire to the iron pot was used as a carrier. After adding oil, seasonings, and dishes, the special tool "spatula" was used to stir the dishes until they were cooked. For stir-frying, one could choose different dishes and seasonings according to one's taste and preference, such as shredded pork, vermicelli, bean sprouts, and so on. In the search results provided, there were some home-cooked stir-fry recipe resources. One could learn how to make all kinds of delicious stir-fried dishes. The specific cooking method and steps could be referred to these recipes.
One of the main themes is adventure. Since rengoku is often involved in battles and dangerous situations, the fanfics may take the reader along on these adventures. They might face demons together and their relationship develops through these shared experiences. Also, loyalty is a big theme. Rengoku is a very loyal character, and this loyalty extends to his relationship with the reader in the fanfics.
Well, some popular rengoku x reader fanfics can be found on Wattpad as well. Look for ones with high ratings and good reviews. They usually offer different storylines, from adventure - filled ones where rengoku and the reader go on quests together, to more romantic and heart - warming stories about their relationship.